Your "Notice" Is Missing: Detecting and Fixing Violations of Modification Terms in Open Source Licenses during Forking

Open source software brings benet to the software community but also introduces legal risks caused by license violations, which result in serious consequences such as lawsuits and nancial losses. To mitigate legal risks, some approaches have been proposed to identify licenses, detect license incompatibilities and inconsistencies, and recommend licenses. As far as we know, however, there is no prior work to understand modication terms in open source licenses or to detect and x violations of modication terms. To bridge this gap, we rst empirically characterize modication terms in 48 open source licenses. These licenses all require certain forms of "notice" to describe the modications made to the original work. Inspired by our study, we then design LV to automatically detect and x violations of modication terms in open source licenses during forking. Our evaluation has shown the eectiveness and eciency of LV. 18 pull requests for xing modication term violations have received positive responses. 8 have been merged. CCS Concepts • Software and its engineering ! Software libraries and repositories; Software conguration management and version control systems; Software evolution; Software maintenance tools.